Reconditionable container



April 14, 1970 Filed June 28. 1967 F. E. ULLMAN RECONDITIONABLECONTAINER 2 Sheets-Sheet 1 April 14, 1970 F. E. ULLMAN 3,505,722

RECONDITIONABLE CONTAINER I Filed June 28, 1967 2 Sheets-Sheet 2'iin'....lnn

United States Patent 3,505,722 RECONDlTIONABLE CONTAINER Frederick E.Ullman, Winnetka, lll., assigner to Inland Steel Corporation, Chicago,lll., a corporation of Delaware Filed June 2.8, 1967, Ser. No. 649,714Int. Cl. B231) 7/00 U.S. Cl. 29-401 22 Claims ABSTRACT 0F THlEDISCLQSURE The present invention relates in `general to shippingcontainers and more particularly, to multi-trip metallic shippingcontainers of the cylindrical or drum like type, genw erally having acapacity on the order of to 55 gallons, and which are commonly shippedwithout an overpack, and to methods of assembly and disassembly thereof.In its principal aspect, the invention is concerned with improvedmethods of assembly and disassembly of metallic closed or tight-headshipping containers and with the containers produced thereby, wherebythe repetitive removal and/ or replacement of at least one, andpreferably both ends, which are otherwise permanently aiiixed to thecontainer sidewall is made feasible with minimal plastic strain to themetallic closure components so as to permit unimpeded access to thecontainer interior for all reconditioning purposes, yet wherein the samemetallic container components may be reused many times without sacrificeto container performance or integrity.

Metallic shipping containers are widely used for packaging, storage andtransport of materials such, merely by way of example, as crude oilproducts, food products, liquid chemicals, paints and other liquid,semiliquid, pulverous or granular materials. In use, these containersmay become damaged, dented or otherwise deformed. The contents are alsofrequently of the character which, once removed from the container,leave a residue that cannot satisfactorily be removed when attempting touse the bung hole or similar orifice of but limited size for access toand cleaning of the container interior. Therefore, a larger opening mustbe made which permits the insertion of suitable tools or devices forremoving dents and otherwise reshaping the container walls wherenecessary. To this end, it is known to cut the empty tight-headcontainer into two halves or to cut out the container ends, clean andreshape the parts and again weld the parts together. These processes, inaddition to being complicated, time-consuming and expensive operations,may considerably reduce the capacity of the container when repeatedseveral times. Moreover, such known reconditioning processes are stillsubstantially incapable of coping with the problem of contamination inthe chime crevices of a container even after the container has been cutapart. And, of course, such known reconditioning processes will notpermit of dedenting or similar reshaping processes in the chime region.

It is also known to unfold the folded chime portions of a tight-headdrum so as to permit removal of the head and closure components.However, this procedure has not proved satisfactory for a number ofreasons. For example, the chime portions of a conventional tight-headdrum are normally formed by folding overlapping portions of the drumbody, head and reinforcing members over upon themselves through at leastone, and normally more than one, complete angle of As a consequence,considerable plastic deformation of the metallic components 0ccurs inthe region of the folds even during the initial drum forming operation,which deformation tends to weaken the metal in that area. Thus, when oneattempts to unfold the construction by again bending the metalcomponents through angles of 180 in the opposite direction, the materialis further weakened and, indeed, excessively stretched. Even were itfeasible to do this repetitively on a multi-trip basis, the resultingproduct is not precisely the same each time. And, in any event, itbecomes weaker each time, thereby preventing the commercial use of sucha process. Moreover, where more than one fold is present, such foldsmust be unfolded in successive order and then successively refolded,thus increasing the length of time required for the reconditioningprocess and the complexity of the tooling used.

Recognizing the many difficulties presented by the foregoing processes,it has further been proposed that the chime or similar closurecomponents can be partially unfolded, and a portion thereof cut off.After reconditioning the parts are then welded in place duringreassembly. Again, however, this procedure is time consuming andexpensive and does not, in any event, result in a container which is thesame as the original container.

Those skilled in the art will appreciate from the foregoing and as theensuing description proceeds that the particular problems which havecontinued to plague the industry and with which the present invention isconcerned are peculiar to a particular type of container-viz., a tighthead drum. Thus, such problems are not encountered when dealing withthat classification of shipping container commonly referred to as openhead drums. That is, an open head drum or container is one in which thehead is not permanently affixed to the drum body, but rather it isremovably aixed thereto in such a manner that the head can be easilyremoved. Such open head drums, for example, commonly employ splitclosure rings or the like to secure the head to the body, which ringscan be tightened down by clamping mechanisms, bolts or similar fasteningdevices.

It is a general aim of the present invention to provide an improvedmulti-trip tight-head shipping container and methods of assembly anddisassembly thereof wherein all parts of the container may be readilyassembled and disassembled during manufacturing and subsequentreconditioning processes with minimal plastic strain whereby suchcomponents may be used repetitively on a multitrip basis, yet whereinthe container after each reconditioning operation is identical inconstruction, capacity, form and appearance with the container asoriginally manufactured. Stated another way, it is an object of thepresent invention to provide a tight-head shipping container whichpermits of ease of repetitive assembly and disassembly and wherein thisis accomplished by plastic deformation of a closure component withinprescribed limits.

An associated object is the provision of a multi-trip shipping containerwhich may he easily disassembled and later reassembled in such a manneras to facilitate more eective and economical cleaning and/orreconditioning of the container parts.

lt is a more specilic object of the invention to provide a novel endclosure assembly having components which may be either shrunk orexpanded by plastic strain to tightly seal at least ont and preferablyboth, ends of the container to the container body, with such end closurecomponents also being plastically expandable or shrinkable to permitdisassembly of the container for cleaning and reconditioning.

It is also an object to provide a shipping container as set forth whichhas a reliable and effective seal between the container end and body.

As a consequence of attaining the foregoing general objectives of theinvention, it has been found that ancillary beneiits are also achievedin that the container is of rigid and durable construction and isparticularly reinforced around the periphery of the container ends so asto resist deformation in those areas which are most often subject todamage during transit.

Other objects and advantages of the invention will become apparent asthe following description proceeds, taken in conjunction with theaccompanying drawings, in which:

FIGURE 1 is a perspective view of the upper portion of a tight-headdrum-shaped shipping container embodying the features of the presentinvention;

FIG. 2 is an enlarged fragmentary section of a partially formed joint,commonly referred to as the chime, between the drum head and body of thecontainer shown in FIG. l with the end connecting ring of the chimeshown in solid lines about to be shrunk by a conventional shrinkingmachine from its expanded position to an assembled position as shown inphantom;

FIG. 3 is an enlarged fragmentary section of the chime betwen the drumhead and body of the container shown in FIG. l with a portion of aconventional expanding machine shown in phantom commencing toplastically expand the end connecting ring of the chime from itsassembled solid line position to an expanded or open position asindicated in phantom;

FIG. 4 is an enlarged fragmentary vertical section similar to FIG. 3,but here depicting a slightly different expanding procedure forpermitting removal of the head from the container body wherein theconnecting ring may also be removed;

FIG. 5 is an enlarged fragmentary vertical section similar to FIGS. 3and 4 of a slightly modified chime construction also embodying thefeatures of the present invention;

FIG. 6 is an enlarged fragmentary vertical section similar to FIGS. 3, 4and 5 of still another modified form of chime construction embodying thefeatures of the present invention;

FIG. 7 is an enlarged fragmentary vertical section similar to FIG. 5,differing therefrom primarily in that in this exemplary form of theinvention the head is freed for removal from the container byplastically shrinking the reinforcing ring rather than by plasticexpansion of the connecting ring; and,

FIG. 8 is an enlarged fragmentary end view depicting details of anexemplary reinforcing ring particularly suitable for use with the formof the invention shown in FIG. 7.

While the invention is susceptible of various modiiications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and will herein be described in detail. Itshould be understood, however, that it is not intended to limit theinvention to the particular forms disclosed, but on the contrary, theinvention is to cover all modifications, equivalents and alternativesfalling within the spirit and scope of the invention.

Referring now to the drawings, there is shown in FIG. 1 the upperportion of an exemplary tight-head drumshaped shipping container,generally indicated at 10, having a cylindrical body portion 11 adaptedto be closed by an upper drum head 12. Those skilled in the art willappreciate that, while not shown in FIG. 1, the lower end of thecontainer body could be, and normally would be, closed in a similarmanner so as to form a liquid-tight conrainer unit. The containerpreferably is made from sheet steel, although it is apparent that othermaterials could be used as well. The illustrative upper drum head i 12may include a filling and emptying orifice 13 and an air inlet and anescape orifice 14. The openings 13, 14 can be provided with anappropriate removable closure to seal the container after it is iilled.

lIn accordance with the present invention, at least one and preferablyboth of the container drum heads may be readily removed to make fullyaccessible the interior portions of the container and its chime forcleaning and reconditioning thereof, and then may be easily reassembledutilizing the same procedure and forming equipment to form a containerwhich has the same capacity and is indistinguishable from its originalform. In the embodiment illustrated in FIGS. 1 3, the drum head 12 iscupshaped having a generally flat central surface 15 set within the drumbody 11 and a cylindrical sidewall 16 terminating in a curved ange 17which overlaps an outwardly rounded end 20 of the drum body 11 in theregion of the container chime 18. Interposed between the rounded end 20of the sidewall and the curved flange 17 of the drurn head is aresilient sealing member such as an O-ring 21. To reinforce the end 20of the drum body an annular curl ring 22 is permanently crimped in placeby the outwardly folded-over body end 20. Such ring 22 may, and oftenwill be welded directly to the body. The curl ring 22 is formed with acylindrical portion 23 which is held adjacent the outside wall of thebody and a flaring skirt 24 extending outwardly from the body. Ifdesired to additionally strengthen the ends of the container, an endreinforcing ring 25 overlaps the sidewall 16 and curved flange 17 of thedrum head.

ln carrying out one form of the invention and in order to secure thedrum head 12 to the container body 11, an endless end connecting ring(FIG. 2) is provided which may be plastically shrunk around theperipheral edge of the drum head and body end, thereby rigidly holdingthe head and body together in liquid-tight relation so as to form aliquid-tight tight-head container 10. Such end connecting ring 30 isalso plastically expandable to permit removal of the head duringreconditioning of the container and is plastically lshrinkable afterreassembly of said head to again secure the head and body in liquidtightrelation. In the illustrated embodiment, the endless connecting ring 30is formed with a lower horizontal iiange 31 which overlaps curl ring 22and a plastically expandable and contractable portion 32 which includesan upper ange 33. The connecting ring 30 is shown in FIG. 2 in its openor expanded position as indicated by solid lines, during which time itcan be seen that the drum head 12 reinforcing ring 25, and sealingmember 21 are easily removable and replaceable on the end 20 of the drumbody, while the connecting ring 30 will be loosely retained on the drumbody through coaction between the flange 31 and curl ring 22.

After the drum head 12, reinforcing ring 25 and sealing member 21 areproperly assembled on the end of the container, the end connecting ring30 is shrunk to its closed or securing position by any conventionalshrinking machine, there being a portion of such a machine showndiagrammatically in phantom at 35 in FIG. 2. The shrinking machine 35includes an annular series of spaced die segments 36 each mounted on aradially movable carrier 37 which is precluded from axial movement inany conventional manner (not shown). The dies 36 each have a formingarea 38 with a configuration complementary to the desired shape of theouter surface of connecting ring 30 when the ring is in a closedposition. lIn order to impart radial movement to each die segment andcarrier, the carrier is formed with an inclined cam surface 39 whichmates in sliding relationship with a similarly inclined cam surface 39'on an axially movable drive member 40. To plastically shrink theconnecting ring 30 to its closed position the die segments 36 of themachine are placed adjacent the connecting ring and the drive member 40s moved axially downward, thus causing inward radial movement of thecarrier and die segments.

When the connecting ring 30 is in its closed position, as indicated inphantom at 30 in FIG. 2 and in solid lines in FIG. 3, the head 12 isheld tightly against the body end 20. The lower flange 31 of theconnecting ring bears against the end of the skirt 24 of the curlreinforcing ring 22, while the upper flange 33 bears against the endreinforcing ring 25 so that the end reinforcing ring 25, drum head 12,sealing member 21, body end and curl ring 22 are tightly compressedbetween the connecting ring flanges 31, 33. The resilient sealing member21 its thereby compressed between the overlapping portions of the headand body end to create a liquid-tight seal. It will, of course beunderstood by those skilled in the art that suitable axially directedforces may be applied to the components prior to and during theshrinking operation by any suitable equipment (not shown) so as toestablish the requisite compressive loading forces for the seal in whichevent the connecting ring 30 will, upon shrinkage to the solid lineposition shown in FIG. 3, serve to hold the components in place againstthe bias provided by the sealing member 21 so as to maintain aneffective liquid tight seal.

After the container has been used on one or more occasions, thecontainer may be completely and simply disassembled for reconditioningand/or cleaning by expanding the expandable portion 32 of the connectingring 30 to its open position. In order to accomplish this, aconventional expanding machine, a portion of which is diagrammaticallyshown in phantom at 45 in FIG. 3, can be employed. The expanding machine45, which operates in a manner similar to the shrinking machine 35described above in conjunction with FIG. 2, includes a plurality ofannularly-spaced die segments 46 secured on respective radially movablecarriers 47. Each carrier is formed with an inclined cam surface 48which is complementary to an inclined cam surface 49 formed on anaxially movable annular drive ring '50. When the ring 50 is movedaxially downward, outward radial motion is simultaneously imparted tothe carriers 47 and die segments 46, thereby causing plastic expansionof the connecting ring portion 32 to the open position shown in phantomat 30 in FIG. 3 so that the end reinforcing ring 25, drum head 12, andsealing member 21 may be removed as described above.

Referring next to FIG. 4, there has been illustrated an improvedtight-head container construction which is essentially identical to thatdepicted in FIGS. 2 and 3, but wherein the expanding procedure isslightly modified so as to permit removal of the connecting ring 30 fromthe drum body 11 during the reconditioning operation. Thus, in this formof the invention the connecting ring 30 is formed with lower and upperhorizontal flanges 31 and 33 respectively and plastically expandable andcontractable portion 51 which is identical to the portion 32 shown inFIGS. 2 and 3 except that it includes the lower flange 31 rather thanthe upper flange 33. The arrangement is such that when a reconditioningoperation is to be performed, it is merely necessary to position asuitable expanding tool (diagrammatically indicated at 52 in FIG. 4)beneath the flange 31, the tool 52 having an upstanding flange 53adapted to be positioned in the space between the drum body 11 and theinnermost edge 54 of the flange 31. Thereafter, the tool 52 is expandedradially outward by any suitable drive mechanism (not shown) to shiftthe connecting ring 30 from solid line closed position shown in FIG. 4to the phantom open or expanded position 30", whereupon the ring 30 andall of the closure components including the head 12 can be removed fromthe body 11.

It will be appreciated from the foregoing that the container of thepresent invention may be completely disassembled so that no crevicesexist in any of the disassembled parts which, when assembled, form achime 18 having crevices therein. All container components therefore,including the chime components, may be thoroughly and convenientlycleaned and reconditioned. After reconditioning is completed, thecontainer may be easily reassembled utilizing the same components andthe same procedures described above, and the connecting ring at each endwill be plastically shrunk to its securing position. Moreover, it willbe apparent to those skilled in the art that the assembly anddisassembly may be readily accomplished since the design of theassembled container provides room for engagement of the expanding andshrinking tooling.

A slightly modified construction also embodying the features of thepresent invention has been illustrated in FIG. 5. In this embodiment, acylindrical drum body 55 is formed with an outwardly curved extremity 56and is closed by a cup-shaped drum head 57. The drum head 57 has agenerally flat central portion 58 adapted to fit within the cylindricalbody 55 and a cylindrical sidewall portion 59 terminating in a radialflange 60 which overlaps the curved body extremity 56. Interposedbetween the overlapping portions of the head and container end is aresilient sealing member such as an O-ring 61. To reinforce thecontainer structure, a hollow reinforcing ring 62 is fitted within thecup-shaped head 57 immediately adjacent the side wall 59, such ring 62having a radially extending flange 63 which overlaps the drum headflange 60. Of'course, as the ensuing description proceeds it will becomeapparent that the ring 62 need not be hollow as shown. Indeed, it couldbe solid or filled, or it could take any of a variety of other shapesprovided that it includes a portion shaped complementary to the knuckleradius" of the head 57 for supporting the latter and a flange such asthe flange 63.

To secure and seal the head 57 to the end of the drum body 55, an endconnecting ring 65 is shrunk from an expanded posiiton shown in phantomin FIG. 5 at 65' to a closed securing position as shown in solid lines.The connecting ring 65 in this case includes a cylindrical leg 66adjacent to and which may be welded or otherwise aflixed to the outsideof the body 55 and an expandable and shrinkable portion in the form 0f adouble thickness of metal 67 defined by a 180 bend, which doublethickness 67 may be shrung around the flaring drum extremity 56 and theradial flange 63 so that the flange 63, drum head flange 60, sealingmember 61, and flaring body extremity 56 are compressed between theconnecting ring leg 66 and double thickness 67. The sealing member 61 isthereby maintained under compressive loading forces between theoverlapping portions of the head and body to create an effectiveliquid-tight seal. The drum head 57 may be conveniently removed to makethe container interior accessible for reconditioning by plasticallyexpanding the connecting ring 65 to its open position as indicated at 65in FIG. 5. The expanding and shrinking functions may be accomplished byany appropriate tooling of the type described above.

Referring next to FIG. 6, there is illustrated yet another form of theinvention which is similar to tbe embodiment of FIGS. 1-3 except thatthe connecting ring and reinforcing ring are formed integrally with eachother. Thus, a cylindrical drum body 70 is here provided with anextremity 71 which is folded outwardly to embrace one end of a curlreinforcing ring 72., the other end of which is formed with a flaringskirt 73 extending a distance out from the drum body. As in the form ofthe invention shown in FIGS. 1-3, the curl ring 72 could, and normallywould, be welded or otherwise permanently affixed to the drum body 70. Acupshaped drum head 75 closing the end of the body 70 has a generallyflat central bottom surface 76 set within the body, and a sidewall 77terminating in a curved flange 78 which overlaps the body extremity 71.Interposed between the overlapping portions of the body and head is aresilient sealing member 79.

In this embodiment a connecting ring 80 is provided which has areinforcing portion 81 overlying the curved flange 78 and the sidewall77 and nuckle radius of the cup-shaped drum head 75, and an expandableand contractable portion 82 which may be plastically shrunk from anexpaned open position shown in phantom in FIG. 6 at 82 to a closedposition shown by solid lines. The expanable connecting ring portion 82has an extremity in the form of a radial ange 83 which underlies andabuts against the tiaring skirt 73 of the curl reinforcing ring 72 whenthe connecting ring 80 is in a closed position so that the drum headflange 78, sealing member 79, body extremity 71, and curl reinforcingring 72 are securelyheld together by the connecting ring 80. When theconnecting ring portion 82 is expanded to the phantom position 82 shownin FIG. 6 the connecting ring S0, drum head 75, and sealing member 79are removable from the drum body 70. It will, of course, be appreciatedthat to achieve such expansion any suitable tooling may be used such,for example, as that shown diagrammatically at 52 in FIG. 4.

Thus far the invention has been described in connection with diversetight-head container constructions and methods for assembling anddisassembling the same wherein the drum head and some, if not all, ofthe related closure components are rendered removable for reconditioningpurposes by plastic expansion of at least one of the closure components,with the same parts later being reassembled by plastically shrinking atleast one of the closure components to form a reconditioned containerwhich is identical to the original container having essentially the sameform, construction, capacity, appearance, and strength and performancecharacteristics as the original. However, those skilled in the art willappreciate that the invention, in its broadest aspects, is not limitedto the use of shrinking procedures forassembly and expanding proceduresfor disassembly. To the contrary, it is within the scope of the presentinvention to employ plastic shrinking procedures for disassembly andplastic expanding procedures for assembly.

To this end, and as best illustrated' in FIG. 7, there has been depictedand will herein -be described below a modified tight-head drumconstruction which, although generally similar in appearance andarrangement to the modification shown in FIG. 5, here is advantageouslydesigned to permit of disassembly 'by plastic shrinking procedures andreassembly by plastic expansion procedures. Thus, a cylindrical drumbody 85 is here provided with an outwardly liared extremity 86. The endof the body 85 is closed by a cup-shaped head 88 having a generally flatcentral portion 89 set within the drum body, and a cylindrical sidewall90 terminating in an outwardly curved radial iiange 91 having an outsidediameter D1. As here shown the ange 91 at least partially overlies theoutwardly flared extremity 86 of the drum body 85. A resilient sealingmember 92 is interposed between the overlapping portions of the body andhead.

In this form of the invention, there is provided a hollow reinforcingring, generally indicated at 94, having an outer cylindrical sidewall 95blending into a smoothly curved portion 96 adapted to overlie and thusreinforce the sidewall 90 and knuckle radius of the head 8S. The ring 94is further provided with a plastically expandable and contractableportion comprising an upright leg 98 having a reversely `bent shorterleg 99 with the adjacent portions of the legs 98, 99 defining a doublethickness of material. The innermost portion of the shorter leg 99terminates in an outwardly extending radial ange 100 adapted to overliethe radial head flange 91.

For the purpose of holding the container components rigidly together toform a tight-head drum, there is provided a connecting ring 101 which issubstantially identical in construction to the ring 65 shown in FIG. 5.Thus, the ring 101 includes a cylindrical portion 102 adapted to bewelded or otherwise aiiixed to the drum body and a reversely bentdouble-leg portion 104, 105 which forms a double thickness of materialwherein the shorter inner leg 105 overlies the outer peripheral edge ofthe flange 100, thus serving to maintain compressive loading forces onthe closure components including the sealing member 92. For a reasonwhich will become apparent below, the inner leg 105 is dimensioned tohave an inside diameter D2 which is slightly greater than the outsidediameter Dl of the head lflange 91.

The arrangement is such that when the tight-head drum shown by way ofexample in FIG. 7 is to be opened for purposes of reconditioning, it ismerely necessary to apply a radially inwardly directed force to thedouble leg portion 98, 99 of the reinforcing ring (as indicated by thearrow) with any suitable shrinking tooling (not shown). This serves toplastically deform or shrink the annulus defined by the leg portions 98,99 and shifts the reinforcing ring 94 to the dotted line position 94. Asthe leg portions are plastically shrunk to the position indicated at94', the outwardly directed radial ange 100 is carried radially inwardlytowards the axis of the drum fbody 85, thus resulting in withdrawal ofthe outer peripheral edge of the flange from beneath the leg 105 of theconnecting ring 101 and thereby unlocking the container closurecomponents. As a consequence, the reinforcing ring 94, head 88 (the ange91 of which has a smaller diameter D1 than the inside diameter D2 of theleg and gasket 92 may all be removed from the drum body 85, thusexposing the interior thereof for reconditioning purposes.

In order to further facilitate the foregoing plastic shrinking operationand to minimize the force required to effect such shrinking, the liange100 may be formed of a plurality of coplanar radially extending fingers10011, 100b, 100C, 100n (best illustrated in FIG. 8) which arepreferably equally spaced about the double leg portions 98, 99 and whichare spaced apart by relatively narrow slots 106. It will be appreciatedthat with such a construction it is unnecessary to shrink the metalwhich defines the flange 100 b-ut, rather, the fingers will simply shiftinwardly with the leg portions 98, 99. Similarly, during a reclosureoperation force will be applied in the opposite direction so as toplastically expand the leg portions 98, 99 and thus urge the fiangelingers outwardly until their free peripheral extremities are againretained in locking rlngition beneath the short leg 105 of theconnecting ring Those skilled in the art will appreciate that variousmodifications may be made in the foregoing procedures without departingfrom the spirit and scope of the invention. Merely by way of example, itwill be observed upon inspection of FIG. 7 that during a disassemblyoperation it would be feasible to plastically shrink the expandable andcontractable portion 98, 99 of the reinforcing ring 94 while at the sametime the portion 104, 105 of the connecting ring 101 could beplastically expanded. The two plastic deforming operations could eithertake place simultaneously or successively, but in either case the amountof plastic deformation of any given component would be halved, therebyfurther prolonging the useful lives of the components. Moreover, itwould also be feasible to use the same type of plastic deformingoperatione.g. expanding or shrinking-to both disassemble and assemble.Thus, and considering for the moment FIG. 5, it will be recalled that toeffect disassembly of the container the portion 67 of the connectingring 65 is plastically expanded until the latter is in the positiondesignated at 65', whereupon the component parts of the container areseparated and reconditioned. During the reconditioning operation it maybe expedient to restore the connecting ring 65 to its pre-expanded solidline position. At the same time, while the reinforcing ring 62 is beingreconditioned, it may be plastically shrunk in a manner similar to thatdescribed for the ring 94 shown in FIG. 7. Thereafter, upon reassemblyof the components which were separated by plastic expansion, thereinforcing ring 62 can be plastically expanded until the peripheraledge of its radial ange 63 is in locking engagement with the connectingring 65.

It will be appreciated from the forgoing that the container of thepresent invention may be conveniently disassembled, reconditioned andreassembled on numerous occasions with but minimal plastic strain of thecomponent parts. For example, the drum heads shown in FIGS. 2-7 can beremoved or replaced and resealed by plastically expanding or plasticallyshrinking a selected closure component on the order of only 1 to 2percent (such percentage representing an expression of the change indiameter of the plastically deformed component). It has been establishedthat ordinary carbon steel can be expanded and shrunk on the order of 2percent for twenty to thirty cycles without significant loss to thoseproperties necessary for the functions performed by the closurecomponents. It has further Ibeen found that the smaller the plasticstrain, the greater the number of reconditioning operations that can beperformed without sacrifice to the container performancecharacteristics` Conversely, the greater the plastic strain, the fewerthe number of ref conditioning operations that can be performed.However, it has been found that satisfactory results at a minimal levelcan be achieved where the plastic strain is kept below 5 percent. Thus,a shipping container embodying the principles of the present inventionwherein the degree of expansion and contraction is controlled within 5percent will be reconditionable many times without replacement of anyparts, excepting possibly the sealing gasket.

I claim as my invention:

1. The method of forming a reusable multi-trip tighthead shippingcontainer comprising the steps of forming a cylindrical drum body,applying drum heads to the opposite ends of said body to close the samein a liquidtight manner, and securing at least one of said heads to saidbody in liquid-tight overlapping relation therewith by plasticallydeforming an endless metallic closure member in one direction about theperipheral edge of said head and body and so as to rigidly secure saidhead to said body, and plastically deforming said member in the oppositedirection to permit removal of said head from said body andreconditioning of said body.

2. The method of forming a reusable multi-trip tighthead shippingcontainer as set forth in claim 1 further characterized in that saidmember is plastically deformed on the order 2 percent or less.

3. The method of forming a reusable multi-trip tighthead shippingcontainer as set forth in claim 1 further characterized in that thedegree of plastic deformation of said member is less than 5 percent.

4. The method of forming a reusable multi-trip tighthead shippingcontainer as set forth in claim 1 further characterized in thatresilient sealing means is positioned between the overlapping portion ofsaid head and said body end, and compressing .said resilient sealingmeans between said head and said body when said member is plasticallydeformed into a securing position so as to create a liquid-tight sealbetween said head and body.

5. The method of forming a reusable multi-trip tighthead shippingcontainer as set forth in claim 1 further characterized in that saidmember comprises an endless connecting ring and that during said rstplastic deforming step said connecting ring is plastically shrunk tosecure said head to said body, and that during said second plasticdeforming step said connecting ring is plastically expanded to permitremoval of said head from said body.

'6. The method of forming a reusable multi-trip tighthead shippingcontainer as set forth in claim 1 further characterized in that saidmember comprises an endless reinforcing ring and that during said firstplastic deforming step said reinforcing ring is plastically expanded tosecure said head to said body, and that during said second plasticdeforming step said reinforcing ring is plastically shrunk to permitremoval of said head from said body.

7. The method of forming a reusable multi-trip tighthead shippingcontainer as set forth in claim 5 further characterized in that saidconnecting ring comprises an integral unitary portion of a reinforcingring, and that during said plastic deforming steps only the connectingring portion of said reinforcing ring is deformed.

8. The method of disassembling and reassembling a multi-trip tight-headshipping container of the type having at least one drum head secured toa drum body by at least one endless metallic closure member so as topermit reconditioning of the disassembled container componentscomprising the steps of:

(A) plastically deforming said endless metallic closure member torelease said head from said body;

(B) reconditioning the disassembled container components; and,

(C) plastically deforming said endless metallic closure member to securesaid head to said body to form a tight-head shipping container identicalin all respects to the original said multi-trip tight-head shippingcontainer.

9. The method of disassembling and reassembling a multi-trip tight headshipping container as set forth in claim 8 further characterized in thatsaid endless metallic closure member comprises an endless connectingring and that during said step (A) said conecting ring is plasticallyexpanded while during said step (C) said connecting ring is plasticallyshrunk.

10. The method as set forth in claim 9 further characterized in thatupon completion of said step (A) said connecting ring is maintainedloosely captive on said body.

11. The method as set forth in claim 9 further characterized in thatupon completion of said step (A) said connecting ring is removable fromsaid body.

12. The method of disassembling and reassembling a multi-trip tight headshipping container as set forth in claim 8 further characterized in thatsaid endless metallic closure member comprises an endless reinforcingring and that during said step (A) said reinforcing ring is plasticallyshrunk while during said step (C) said reinforcing ring is plasticallyexpanded.

13. The method of disassembling and reassembling a multi-trip tight headshipping container as set forth in claim 8 further characterized in thatsaid endless metallic closure member comprises an integral unitaryreinforcing ring having a connecting ring portion and that during saidstep (A) said connecting ring portion is plastically expanded whileduring said step (C) said connecting ring portion is plastically shrunk.

14. The method of disassembling and reassembling a multi-trip tight-headshipping container of the type having at least one drum head secured toa drum body by first and second metallic closure members so as to permitreconditioning of the disassembled container components comprising thesteps of:

(A) plasticaly deforming at least one of said rst and second metallicclosure members to release said head from said body;

(B) reconditioning the disassembled container compo nents; and

(C) plastically deforming at least one of said irst and second metallicclosure members to secure said head to said body to form a tight-headshipping container identical in all respects to the original saidmulti-trip tight-head shipping container.

15. The method as set forth in claim 14 further characterized in thatduring said step (A) said first closure member is plastically expandedand during said step (C) said lirst closure member is plasticallyshrunk.

16. The method as set forth in claim 14 further characterized in thatduring said step (A) said second closure member is plastically shrunkand during said step (C) said second closure member is plasticallyexpanded.

17. The method as set forth in claim 14 further characterized in thatduring said step (A) said iirst closure member is plastically expandedand said second closure member is plastically shrunk, and during saidstep (C) said rst closure member is plastically shrunk, and said secondclosure member is plastically expanded.

18. The method as set forth in claim 17 further characterized in thatthe plastic expanding and shrinking operatons of step (A) are carriedout simultaneously and in that subsequently the plastic shrinking andexpanding operations of step (C) are carried out simultaneously.

19. The method as set forth in claim 17 further characterized in thatthe plastic expanding and shrinking operations of step (A) are carriedout successively and in that subsequently the plastic shrinking andexpanding operations of step (C) are carried out successively.

20. The method as set forth in claim 14 further characterized in thatduring said step (A) one of said first and second closure members isplastically deformed; that dur- `ing said step (B) said one closuremember is restored to the state it occupied prior to step (A) and theother of said first and second closure members is plastically deformed;and that during said step (C) said other closure mem-ber is againplastically deformed to restore it to the state it occupied prior tostep (B).

21. The method as set forth in claim 20 further characterized in thatduring said step (A) said first closure member is plastically expandedto permit separation of the container components; that during andincident to said step (B) said rst closure member is restored to itspre-expanded state and said second closure member iS o tically expanded;and that during said step (C) said first closure member is plasticallyshrunk to restore it to its pre-expanded state.

References Cited UNITED STATES PATENTS 1,948,920 2/1934 Johnson 220-59 X2,338,013 12/1943 Schrader 220-59 2,943,386 7/1960 Katz 29-401 3,187,7946/1965 Rodish 229-5.7 3,349,952 10/1967 Bijroet 22067 FOREIGN PATENTS948,136 8/1956 Germany.

MARVIN A. CHAMPION, Primary Examiner E. I. MCCARTHY, Assistant ExaminerU.S. C1. X.R. 113-120; 220-67

